A boundary current is a type of ocean current that flows along the boundary between two different regions of water with distinct physical, chemical, and/or biological properties. Synonyms for boundary current include: ocean front, water mass boundary current, frontal current, density current, water boundary layer, and oceanic boundary zone. These types of currents can be found in many of the world's oceans, including the Atlantic, Pacific, and Indian Oceans. They are an important factor in ocean circulation, climate, and ecosystem dynamics. Understanding their complex interactions with other ocean currents is essential to modeling and predicting global ocean conditions and climate change.